Highly filled injection moldable polyetherketones

Abstract

Injection moldable, highly filled polymer composites are provided which exhibit high dimensional stability at temperatures above the glass transition temperature of the matrix polymer. The heat distortion temperature of the composites approaches that of the crystal melting temperature of the matrix polymer. The composite includes a polyaryletherketone matrix and at least two types of fillers each providing unique properties. The first filler is a reinforcing fiber filler which provides high strength and stiffness. The second filler is an non-thermoplastic immobilizing filler to immobilize the amorphous portion of the partially crystalline polyaryletherketone polymer and provide resistance to high temperature distortion. Notwithstanding its improved mechanical and heat resistant properties, the composite remains injection moldable and thus capable of low cost manufacturing.

Claims

1. A polymer composite for molding articles having improved strength and resistance to heat distortion comprising:

a) a partially crystalline and partially amorphous polyaryletherketone polymer,

b) a reinforcing fiber for providing strength and stiffness to the molded article,

c) an immobilizing filler for immobilizing the amorphous portion of the polyaryletherketone polymer to provide additional stiffness and dimensional stability at elevated temperatures, and

d) said reinforcing fiber and said immobilizing filler forming at least 40% of the volume of the composite and raising the heat distortion temperature at 264 psi of the composite to above 300.degree. C. and having a melt viscosity of less than 10,000 poise at 1000 sec.sup.-1 at 430.degree. C.

2. The composite as claimed in claim 1 wherein the polyaryletherketone polymer is selected from the group consisting of polyetherketone, polyetheretherketone, polyetherketoneetherketoneketone, polyetheretherketoneketone and polyetherketoneketone polymers.

3. The composite as claimed in claim 1 wherein the reinforcing fiber is selected from the group consisting of glass fibers and carbon fibers.

4. The composite as claimed in claim 1 wherein the immobilizing filler is selected from the group consisting of equiaxed and platelet shaped particles.

5. The composite as claimed in claim 1 wherein the immobilizing filler has no dimension larger than 200.mu.m.

6. The composite as claimed in claim 1 wherein the volume percentage of reinforcing fiber does not exceed 25%.

7. The composite as claimed in claim 1 further including a solid lubricant filler.

8. The composite as claimed in claim 7 wherein the solid lubricant is selected from the group consisting of graphite, molybdenum disulfide, and boron nitride in powder form.

9. The composite as claimed in claim 1 wherein the total volume content contributed by the reinforcing fiber and the immobilizing filler is between 40 and 60%.

10. A composite as claimed in claim 1 wherein the composite has a melt viscosity of less than 7500 poise at 1000 sec.sup.-1 at 430.degree. C.

11. A polymer composite for molding articles having improved strength and resistance to heat distortion, formed from a homogenous mixture comprising:

a) a partially crystalline and partially amorphous polyaryletherketone polymer,

b) a reinforcing fiber for providing strength and stiffness, said reinforcing fiber comprising less than 25% by volume of the article.

c) a non-thermoplastic immobilizing filler for immobilizing the amorphous portion of the polyaryletherketone polymer, said immobilizing filler being selected from the group consisting of equi-axed and platelet shaped materials; and

d) said reinforcing fiber and said immobilizing filler forming at least 40% by volume of the composite and raising the heat distortion temperature of the composite at 264 psi to above 300.degree. C. and within 20.degree. C. of the crystalline melting point of the polyaryletherketone polymer and having a melt viscosity of less than 10,000 poise at 1000 sec.sup.-1 at 430.degree. C.

12. The composite as claimed in claim 11 wherein the polyaryletherketone polymer is selected from the group consisting of polyetherketone, polyetheretherketone, polyetherketoneetherketoneketone, polyetheretherketoneketone and polyetherketoneketone polymers.

13. The composite as claimed in claim 11 wherein the reinforcing fiber is selected from the group consisting of glass fibers and carbon fibers.

14. The composite as claimed in claim 11 wherein the immobilizing filler is selected from the group consisting of mica, graphite flakes and calcium terephthalate.

15. The composite as claimed in claim 11 wherein the immobilizing filler has no dimension larger than 200.mu.m.

16. The composite as claimed in claim 11 further including a solid lubricant.

17. The composite as claimed in claim 16 wherein the solid lubricant is selected from the group consisting of graphite powder, molybdenum disulfide and boron nitride.

18. The composite as claimed in claim 11 wherein the volume percentage of the reinforcing fiber and the immobilizing filler is between 40 and 60%.

19. A polymer composite for producing melt processable articles having improved strength and resistance to heat distortion formed from a homogenous mixture comprising:

a) a partially crystalline and partially amorphous polyaryletherketone polymer,

b) a reinforcing fiber filler for providing strength and stiffness, said filler comprising less than 25% by volume of the article.

c) a platelet shaped immobilizing filler for immobilizing the amorphous portion of the polyaryletherketone polymer, and

d) said reinforcing fiber and said immobilizing filler forming at least 40% by volume of the composite and raising the heat distortion temperature of the composite at 264 psi to above 300.degree. C. and having a melt viscosity of less than 10,000 poise at 1000 sec.sup.-1 at 430.degree. C.

20. The composite as claimed in claim 19 wherein the platelet shaped immobilizing filler is selected from the group consisting of graphite, talc, mica, synthetic hectorite, silicon carbide and melt derived polybenzimidazole thermoplastic particles.